Dual switch heat controlling attachment



July 17, 1956 s. BIRK 2,755,360

DUAL SWITCH HEAT CONTROLLING ATTACHMENT ATTO R N EY July 17, 1956 s. BIRK DUAL SWITCH HEAT CONTROLLING ATTACHMENT 2 Sheets-Sheet 2 Filed March 30, 1953 so e2 5e FIG 54 4452 54 e 4o 4e' 422 |26 |22 64 34 22mm 02 |00 |24- 72 9o no 78 36 |2 lo'a/ :0'4111 es e2 |06 |38 30m 28 G @Wise Flc-5.6.

A f-ve O O no /I l\ 4 l2 C G G Flg,

INVENTOR son. Bmx, BY

ATTORNEY United States Patent O DUAL SWITCH HEAT CONTROLLING ATTACHMENT Sol Birk, Bronx, N. Y.

Application March 30, 1953, Serial No. 345,585

1 Claim. (Cl. 200-140) This invention relates to a thermostatic means for controlling heat in heating units and has particular reference to a dual switching means for controlling and fixing either one of two temperatures in a unit being heated.

The essential object of the present invention contemplates an electrical switching means having dual contact points engageable with adjustable terminal elements which may, after adjustment, be fixed in position and which are actuated to make or break an electrical circuit by means of an expansible vapor unit.

A further object of this invention resides in the provision therein of a spring contact arm which is fixed at one end to a base member and extends freely therefrom, and has two contact points upon its free end which are adapted to engage with dual complementary contact points upon the ends of threaded rods, the said threaded rods being adjustable and adapted to vbe held in a fixed position after adjustment, the said spring contact arm and said threaded rods having electrical connection with conductors to an electric source.

A still further object of the present invention is the provision in same of the means for combining a conventional expansible unit with the device above set forth to actuate the said spring contact arm to make or break an electric circuit between either of the contacts upon the said spring contact arm and the complementary contacts upon the said adjustable rods.

The best embodiment of the invention has been chosen for illustrative purposes, but this embodiment should be viewed as being illustrative only and not as limiting because obviously the invention is capable of other embodiments having revised details of construction, so long as they fall within the ambit of the appended claim.

The invention itself, however, both as to its organization and its method of operation, will best be understood from the following description of a specific embodiment when read in connection with the accompanying drawing, in which:

Fig. l is a top or plan view of a thermostatic heat controlling apparatus having dual make or break contact means, the electrical hook-up being diagrammatically shown;

Fig. 2 is a front elevational view of same;

Fig. 3 is an end elevational View looking in the direction indicated by arrow x of Fig. 2;

Fig. 4 is a similar View looking at the opposite end or in the direction indicated by arrow y of Fig. 2;

Fig. 5 is a longitudinal sectional view taken along a plane as indicated by line 5-5 of Fig. 1;

Fig. 5a is an enlarged fragmentary detail of a part which will be hereinafter explained;

Fig. 6 is a plan view of the base member of the apparatus;

Fig. 7 is a plan view of a spring contact arm detached from the base;

Fig. 8 is a plan View of a part hereinafter known as a holding plate, and

Fig. 9 is an end elevational view of the base and is taken,

2,755,360 Patented July 17, 1956 ice looking in the direction indicated by the arrow A of Fig. 6 and shows in addition an angular cover plate which is attachable to the base but shown in the drawing as detached therefrom.

Referring to the parts, in detail, in which similar reference numerals refer to similar parts throughout, 10 designates the thermostatic unit in general, in which 12 comprises a base member having an elevated platform 14 at one end, and an upstanding portion 16 which forms a side wall to an open ended enclosure portion 18. The reference numeral 20 designates an angular member comprising a depending portion 22 forming the opposite wall of said enclosure 18 and a top portion 24 forming the cover portion of the said enclosure, screws 26 secure the said angular member 20 to the base 12, and wall 16.

Upon the base 12 at the end opposite the platform 14 and to one side of the said base there is formed an upstanding portion 28 having a shelf-like top 30 to which there is attached, by screws 32, a bracket 34, of Bakelite or other suitable insulating material, which projects over the said base 12 and is best shown in Figs. 1 and 3. To the said bracket 34 there is secured, by means of screws 36 and 38, terminal lugs 4t) and 42 respectively. The said terminal lugs are formed with upstanding tubular sections 44 and 46 respectively (shown in section in Figs. 5 and 5a). The inner surface of said tubular sections are each lined with a collar 48 and 50, respectively, of fiber or other resilient material. Threaded orifices 52 and 54 are formed at the tops of said tubular sections 44 and 46 through which adjustable threaded rods 56 and 53 engage and have electrical connection with the said lugs 4t) and 42 respectively. Knobs 60 and 62 are attached to the upper ends of the said rods and provide finger holds for rotating the said rods. The lower ends of said rods 56 and 58 are broadened as at 64 and 66 and form terminal contact points which may be vertically adjusted by rotating the rods upon which they are formed. The aforementioned fiber linings 48 and 50 have a tight frictional grip upon the threads of the rods which are threaded through them and are adapted to prevent any displacement after manual adjustment. Attachment orifices 68 and 70 may be provided in the base 12.

A spring contact arm 72 is secured to the platform 14 upon the base 12 and is held thereon by a holding plate 74 and screws 76. The said spring contact arm 72, holding plate 74 and screws 76 are insulated from the base 12 by means of an insulating plate 78 of Bakelite or other suitable insulating material, as for instance, mica washers 80 and mica filler rings 82 (Fig. 5). The holding plate 74 and the attached end portion of the spring contact arm 72 are formed with orifices 84 and 86 respectively that are slightly larger in diameter than the diameter of the screws 76 which engage through them to threaded bores 88 in the base 12. The said filler rings 82 engage and encircle the screws 76 and insulate same from the said spring contact arm 72 and the holding plate 74. One end of the said holding plate 74 projects beyond the end of the base to form a lip 90 which is provided with an attachment bolt and nut 92 to form a means for attaching a feed wire 94 which directs an electric current, to the control unit, from its source.

The said spring contact arm 72 extends freely from the said platform 14 to a point slightly beyond and under the aforesaid contact points 64 and 66 formed upon the rotatable rods 56 and 58. The said spring contact arm 72 is formed by means of a U-shaped slit 96, with an auxiliary contact arm or tongue 98 (Figs. l and 7), upon the free end of which there is formed a contact point 100 which is aligned with its complementary contact point 66 upon the lower end of the rotating rod 58. A second contact point 102 is formed upon the outer end of the said spring contact arm 72 and is aligned with its complementary contact point 64 upon the lower end of said rotating rod 56. To add to the ilexibility of the said spring contact armr72, the same has formed thereon a transverse groove or depression 104 in juxtaposition to the aforesaid platform 14 (Figs. 5 and 7). An eyelet 106, insulated by mica washers and ller ring 108 from the spring contact arm 72, is secured upon the said spring contact arm (Figs. and 7).

A plate 110 of any suitable insulating material is cemented or otherwise secured upon the base 12 at its end and directly beneath the free ends of the spring contact point 72 and the auxiliary arm 98.

A double-throw, two-point switch 112 (Fig. l) may be provided upon a frame upon which the control unit may be mounted and is connected upon one side to the terminal 42 by a line 114 while the terminal 40 connects by line 116 to the opposite point of the said double-throw switch 112. The pivoted arm of the switch 112 connects, by means of the line 118, to the electric supply source.

A conventional expansible unit 120 comprising an upper and a lower diaphragm 122 and 124 respectively, has a hollow boss 126 secured to the upper diaphragm (Fig. 5) 122. The said boss forms a compartment which connects, through a port 128, with the interior space between the said upper and lower diaphragm. To the top of said boss there is secured an upstanding pin 130 which is engageable within a bore 132 upon a threaded rod 134. The said rod 134- is threaded through the top 24 of the aforesaid enclosure member 18 and may be locked thereon by a lock nut 136. To the lower diaphragm 124 of the expansible unit there is secured a depending lug having a conical end 138 which is adapted to engage the aforesaid eyelet 106 upon the spring contact arm 72.

An elongated tube or bulb 140 is sealed at one end 142 and has connected to its opposite end a contracted tube 4 or capillary 144 which leads to and is connected with the hollow boss 126. The saidbulb is placed in close proximity to the heat controlled element. It is desirable at times to control the heat at the element to be heated under one of two fixed temperature controls. To accomplish this, a unit having two circuits and dual controlling contacts (either one of which may be put in operation by adjusting the dual contact points at the temperatures desired and fixing same securely in position, which cooperating with the action of the expansible unit), is employed to regulate or maintain the predetermined heat at the element being heated.

I claim:

The combination with a switch controlling unit cornprising an expansible element actuated by the expansion or contraction of a diaphragm in said expansible unit, a base plate having a raised platform at one end, a spring Contact arm having dual contact points upon its free end, dual adjustable rods having contacts points adapted to engage said dual contact points upon the said spring contact arm, and means comprising an adjustable pin engageable with the said expansible unit and said spring contact arm to regulate the tension upon said spring contact arm.

References Cited in the le of this patent UNITED STATES PATENTS 510,889 Butz Dec. 19, 1893 2,068,093 Terjesen Jan. 19, 1937 2,288,517 Dubilier June 30, 1942 2,341,931 Lloyd Feb. 15, 1944 2,374,097 Holmes Apr. 17, 1945 2,586,992 Rapuano Feb. 26, 1952 

